1. Technical Field
The disclosure generally relates to earphone jack circuits, and particularly to an earphone jack circuit for a portable electronic device having a frequency modulation (FM) function.
2. Description of Related Art
A portable electronic device such as a mobile phone commonly comprises a FM function. When a built-in FM antenna is installed in the mobile phone, the built-in FM antenna may be susceptible to interference from other electronic components inside the mobile phone because a volume of the mobile phone is limited and which may lead to negative influences on a FM performance of the mobile phone. Thus, an external FM antenna is usually used in the mobile phone to realize the FM function.
To simplify an external structure of the mobile phone, an earphone of the mobile phone is used to severe as the external FM antenna to receive FM signals. However, most earphones severed as the FM antenna have relative lower sensitivities while receiving FM signals than the special external FM antennas and the mobile phone may be difficult to obtain a desired FM performance.
Therefore, there is room for improvement within the art.